OK, so, I have been doing some research recently, well, the past week on beavers. I am quickly learning that they absolutely fascinate me and just might be my favorite creature!! Anyway, to the subject at hand.

I read a paper tonight(scientific, primary literature) that I found Extemely informative and insightful. and it also prompted questions. This paper talked about castor sacs and anal glands in beaver. Long and short of the story is that the chemical composition of the castor changes seasonally and is dependant on the diet of the beaver. Anal gland secretions do not change chemically during the life of the beaver, and both are deposited at scent mounds.

The realy cool thing is that beaver can identify relatives/siblings by the chamical composition of the anal gland secreitons(AGS), but are not really able to do so by the castor juice. And they ID siblings that they have never "met" so to speak. Further, mates can ID the siblings of their mate through the AGS.

Even better, is that when 2 fake scent mounds were made, side-by-side, and one was annointed in a sibling's AGS, and the other dripped on by a total stranger's AGS, the resident beaver spent much mroe time and energy defacing the non-sibling's castor mound!! And this paper reported that AGS recieved just as an aggressive response as the castor, and maybe a little more of an aggressive response.

So my question: I have heard a lot on here about castor sacs, and collecting them, and using them as bait. But I have never heard anyone talk about Anal Glands. Why dont you guys take them????? Why arent they used???

Look at this picture, you can see they are smaller, but.....?????????

And, here is a link to the paper. please let me know if you cant open it, and I will email it to all those interested, if you PM me. And ooh, yeah, we sould have a file upload option on these posts, so we can attach stuff, just like an email. Click on the "download Pdf" link to open the article.

It appears that what you're calling an anal gland is instead the oil sac. This is where the beaver's oil is stored that it uses to waterproof its fur.

If you look at the third toe on the back feet of the beaver, you will see the toenail is actually a double toenail and this is used to "comb" the oil into its fur. This oil is unique in smell and works well at attracting beavers. I have used the oil from a family member on many occasions when I have one smart beaver left. When it smells the oil from one of the family members that it hasn't seen in awhile, the beaver tends to respond well when it won't respond to any other lures.

This link will show you where the glands are on a real beaver and what they look like....

By what criteria was the response to the castor mounds rated ? It seems to me that it could be a situation ripe for subjective interpretation and a biased judgement. Hope you can provide an explanation.

White17, Here is a direct copy paste from the article. I might be able to copy-paste the entire article into a post. I'll try it.

"A complete beaver response to experimentalscent mounds can be sequentially separated into"sniffing (normally within 30 cm of the scentmound), straddling (standing on the mound onhind feet), pawing and, occasionally, overmarking(putting a pile of mud either at the side or on topof the original scent mound and then marking itwith castoreum and probably with AGS, too).Weaker responses, however, consist of only theearlier parts of the sequence. We thus usedresponse completeness (the number of differentbehavioural patterns in a response) to measureresponse intensity."

If the observer had knowledge of which mound was which, he could obviously view behavior to skew the results to agree with the hypothesis. Not saying they did, but it would have been better if the observations were done by someone with no knowledge of the difference in the mounds. For all I know, maybe they did it that way.

There is some indication that grizzly bear males can recognize their offspring and refrain from killing them. I can see where this could apply to all critters.

Anim. Behav., 1997, 54, 493–502Sibling recognition in the beaver: a field test for phenotype matchingLIXING SUN & DIETLAND MU} LLER-SCHWARZEDepartment of Biology, College of Environmental Science and Forestry, State University of New York(Received 6 June 1996; initial acceptance 31 August 1996;final acceptance 13 November 1996; MS. number: A7624)

Abstract. The hypothesis of kin recognition by phenotype matching predicts that relatives can beidentified without previous contact, and/or that cues used for recognition can be learned indirectly froma third but related individual. This hypothesis was tested in the field using 22 beaver, Castor canadensis,families. Individually identifiable beavers were provided with a two-way choice between two experimentalscent mounds, one of which was scented with the anal gland secretion (AGS) from an unfamiliarsibling of the test subjects, the other with AGS from an unfamiliar non-relative. Beavers showed lessstrong territorial responses to AGS from their siblings than to that from non-relatives. The mates of thetest subjects, which were not related to, or familiar with, either of the AGS donors, also responded lessstrongly to the AGS from their mates’ siblings than to that from other unfamiliar non-relatives. Thisdiscrimination was not shown when castoreum samples were tested instead of AGS. Therefore, it wasconcluded that (1) information about kinship in the beaver is coded in the AGS but not in thecastoreum, (2) the mechanism of phenotype matching is used in beaver sibling recognition, and (3) thecue used in phenotype matching can be learned and used for recognition of related individuals by anunrelated individual. ? 1997 The Association for the Study of Animal Behaviour

Hamilton (1964) proposes that an animal shoulddo a favour for its relatives according to thedecision rule b/c>1/r, where b and c are the benefitto the recipient and cost to the donor associatedwith the altruistic behaviour, respectively, and r isthe coefficient of relatedness between the benefitdonor and recipient. One assumption behindHamilton’s rule is that the degree of relatedness(r) is recognizable, actively or passively. Thisassumption has stimulated extensive testing forkin recognition abilities in numerous species,typically with a two-way choice setting in thelaboratory. Laboratory studies facilitate the controlof variables, but they may also confoundresults with artefacts, two of which are highlightedby Waldman (1987): subjects may be presenteda task that does not naturally exist, and theontogeny of kin recognition is often ignored.Laboratory environments may also modify thephysiological status, and hence alter the responsepattern, of subjects. These constraints are particularlytrue for mammals, which show a higherdegree of behavioural plasticity than any otheranimal taxon. Field studies are therefore importantfor consolidating and integrating laboratoryfindings in a natural context.The beaver, Castor canadensis, is among the fewmammalian species that are excellent models forbehavioural studies in the field (Mu¨ ller-Schwarze& Houlihan 1991; Schulte 1993). It is a centralplaceforager (Jenkins 1980) with a small activitycore area consisting of one or several connectedponds, which are also its territory. These traitsfacilitate close-range observation and accuratedata acquisition. Beavers live in family units,consisting of an adult pair and their offspring. Thetwo breeding adults give birth to 3–4 kits onaverage in early summer every year. Two-year-oldmale and female offspring disperse from theirnatal families (reviewed in Jenkins & Busher1979). Dispersal is assumed to occur alongstreams (Townsend 1953; Leege 1968). Becausebreeding adults can live as long as 9 years in thesame place (Svendsen 1989) and dispersers appearto resettle in a suitable habitat that is close to theirnatal families (L. Sun unpublished data), dispersersof different years from the same family arelikely to meet outside their natal colony sitewithout knowing each other. Since altruism andavoidance of extreme inbreeding can increasefitness (Hamilton 1964; Bensch et al. 1994), thisbenefit calls for mutual recognition betweenrelated individuals without previous contact.Social interactions between beavers are largelyregulated by chemical signals. At some locationsalong the shoreline of beaver ponds, beavers regularlyplace piles of mud or grass and then markthem with secretions to advertise their territory(Mu¨ ller-Schwarze & Heckman 1980; Svendsen1980; Mu¨ ller-Schwarze & Houlihan 1991). Membersof different families have little interactionexcept for late spring, when dispersal starts. Duringthis time, residents mark vigorously to advertisetheir territoriality, and tens of fresh scentmarks can be found at one time. Marking activitytapers off later, and only a few marks can befound in late summer and autumn (Hodgdon1978; Houlihan 1989). New territory owners,however, frequently mark their territories independentof seasons (L. Sun, unpublished data).Therefore, the presence of scent marks signal theownership of the area.The beaver has two well-defined pheromonesources, anal gland secretion (AGS) and castoreum,both located at the cloaca area. The analgland is sebaceous with wax esters and fatty acidsbeing major constituents. The gland is sexuallydimorphic and is not influenced by age (Sun1996). The castor sac where castoreum is stored,however, lacks secretory epithelium (Walro &Svendsen 1981). Evidence shows that castoreum iscomposed of compounds that are probablydietary derivatives (Mu¨ ller-Schwarze 1992) andseems not to be sexually dimorphic. Beaversactively deposit castoreum while marking, buthow the AGS is deposited needs to be clarified. Astrange conspecific’s AGS or castoreum can elicitterritorial responses (Hodgdon 1978; Welsh &Mu¨ ller-Schwarze 1989) but secretions from amember of the same family have little effect ineliciting behavioural responses (B. Schulte, personalcommunication). Information about sex orindividuality are suspected to be contained inbeaver secretions (Hodgdon 1978; Welsh &Mu¨ ller-Schwarze 1989).Kin can be recognized by the following mechanisms:(1) recognition by spatial distribution, (2)recognition by social learning, (3) recognition byphenotype matching, and (4) recognition by recognitionalleles (reviewed in Halpin 1991). Mechanism1 is a passive process and not applicable toour scenario. Mechanism 4 is of theoretical interestbut may not exist in the real world (Blaustein1983; Holmes & Sherman 1983; Waldman 1987).Mechanism 2 requires previous contact, which isunlikely to be involved in recognizing unfamiliar,earlier- or later-born relatives. In mechanism 3, ananimal recognizes its relatives by comparing thesimilarity between a cue it has learned earlier(template) and the label(s) the relatives carry. Kinrecognition through this process does not requireprevious encounter, and thus phenotype matchingis most likely to be used by beavers to recognizeunfamiliar relatives outside their natal families. Ifbeaver secretions are used in kin recognition bythe mechanism of phenotype matching, we predictedthat (1) beavers show reduced territorialresponses to secretions from relatives even withoutprevious contact, and (2) cues used for discriminationcan be learned from a third individualthat is related to the test subject (Holmes &Sherman 1983; Blaustein et al. 1987). If the secondprediction is true, we expected that the cues usedfor kin discrimination between relatives can alsobe learned by unrelated individuals. To test thetwo predictions, we conducted a field experimentusing the method of two-sample choice test.METHODSSample CollectionWe trapped 116 beavers using Hancock livetraps baited with aspen, Populus tremuloides,twigs at Allegany State Park, New York, from1992 to 1995. We weighed and anaesthetizedcaptured beavers with a xylazine and ketaminemixture injection (0.67 and 6.7 mg/kg bodyweight, respectively). After immobilization, wesexed beavers by the colour and viscosity of AGS(Schulte et al. 1995) and cross-validated the resultsby palpating for the presence or absence of the ospenis (Osborn 1955). We assigned beavers to ageclasses (kit, 1 year old, 2 year old and adult) basedon body weight and size (Schulte 1993). Both earsof each individual were tagged with a uniquecolour combination of anodized aluminium eartags (National Band & Tag Co., Kentucky). Thus,all beavers in the 22 families (average familysize=3.5; range=2–6) used in our study wereindividually identifiable. Because trapping hadbeen carried out every year since 1984, and the lifehistory of most beavers had been monitored from494 Animal Behaviour, 54, 3a few months after they were born, the exactgenealogical relationships within the 22 famiieswere known. We milked secretion samples fromthe left and right anal glands and castor sacsseparately into three 10-ml vials and allowed2 hours for beavers to fully recover from theanaesthetics before release. We dissolved eachsecretion sample with methylene chloride (1:5 byvolume) and stored it in a "20)C freezer untiluse. For the field bioassay, we diluted the solutionwith methylene chloride (1:4 by volume) and thenused 0.25 ml for each application. Pilot studiesshowed that this concentration was well above theresponse threshold of the beaver.Experimental SettingTo investigate discriminatory abilities of thebeaver, we designed a two-sample choice test andmeasured territorial responses of resident beaversas the dependent variables. We constructed twoexperimental scent mounds and treated them withbeaver secretions to mimic the presence of intruders(Fig. 1). We chose 30 cm as the distancebetween the two scent mounds to ensure that oncea beaver responded to one of them, it would alsorespond to the other; hence, between-treatmenteffect could be compared. We used a size 18 corkin each experimental scent mound to hold scentmaterials and to control the evaporation surfacearea (12 cm2).Using the above experimental setting, we comparedbeaver responses to scents (AGS or castoreum)from unfamiliar siblings with responsesto those from unfamiliar non-siblings. Scentdonors were siblings with at least 2 years’ agedifference, so they had had no previous interactionsbecause the older siblings dispersed beforethe younger ones were born (Fig. 2). We playedback the scents from older siblings to the youngerones (at their natal sites) and the scents from theyounger siblings to the older ones (at the oldersiblings’ new sites). In both situations, we treatedone experimental scent mound with the scent froman unfamiliar sibling (treatment) and the otherscent mound with the scent from an unfamiliarnon-sibling collected from a remote site (>6 km;control). We defined a remote site as that beyondthe average disperal distance (6.21 km: L. Sun,unpublished data).In the second test, we used the same scentdonors and settings as the above, except that therecipients were the older siblings’ mates, whichwere not genetically related to, or had had anyprevious contact with, either of the scent donors(Fig. 2). This experiment was to test whetherbeavers can use cues that they experienced fromtheir mates to discriminate between scents fromunfamiliar, younger siblings of their mates andscents from unfamiliar non-relatives.We used 10 families from 1994 and 12 familiesfrom 1995 for bioassays in the spring and summer,when marking activities were relatively high. Wereapplied the same pair of secretion samples butwith randomized assignments to the two experimentalscent mounds to bioassay at each familyon 6 consecutive days. Each beaver family wasused only once per year. Because AGS profiles aresexually dimorphic, secretion samples used in theexperiments were from adult males (§2 years) toavoid possible biases.Recording and Data AnalysisWe set up two pairs of experimental scentmounds, one for AGS and the other for castoreum,at two different locations on the bank ofa beaver pond about 30 min before beavers begantheir late afternoon activity (at 1700–1800 hours).We used a Tandy 102 laptop computer loadedwith the program Observer 2.0 (Noldus InformationTechnology, The Netherlands) to record eachresponse pattern and duration. In a few cases ofmultiple responses, where two or more beaversresponded sequentially to experimental scentmounds, we included only the response of the firstbeaver in our analyses because physical damageto the scent mound (pawed, flattened or obliterated)might cause some carry-over biases in thefollowing responses. Observation ended at 2100hours, when fading daylight prevented individualidentification.A complete beaver response to experimentalscent mounds can be sequentially separated intosniffing (normally within 30 cm of the scentmound), straddling (standing on the mound onhind feet), pawing and, occasionally, overmarking(putting a pile of mud either at the side or on topof the original scent mound and then marking itwith castoreum and probably with AGS, too).Weaker responses, however, consist of only theearlier parts of the sequence. We thus usedresponse completeness (the number of differentbehavioural patterns in a response) to measureresponse intensity. Because the latter three patternswere performed less frequently and involveddirect contact with the experimental scentmounds, they were pooled and collectively named‘physical response’. Normally, we included onlyone individual from each family in our analyses.Because responses to treated and control sampleswere paired and the variables of interest were thedifference in response of the two scent mounds,rather than the absolute time responding toeach of the scent mounds, occasional repeatedmeasurements should not mask beavers’ discriminatoryabilities. Since the response time was notnormally distributed, we used the Wilcoxonsigned-ranks test to examine the treatment effect.The sign test was used to determine the significanceof the difference in beavers’ response completeness.For each treatment, we compareddifferences between the two sexes for sniffing,physical and total responses using the Wilcoxontwo-sample test. We later pooled male and femaleresponses in our analyses because no significantdifference was detected. Since our hypothesis predictsthat beavers show reduced territorial behaviourdue to relationship or familiarity, all testswere one-tailed with a significance level of 0.05,

RESULTSBeavers (dispersers or the siblings of dispersers)spent significantly less time responding to siblings’AGS than to non-relatives’ AGS (Wilcoxonsigned-ranks test: T=66, N=22, P<0.020). Thiswas due to a shorter physical response to (T=65,P<0.030), but not sniffing (T=102.5, P>0.100),siblings’ AGS (Fig. 3). We also found a lowerdegree of response completeness when beaversresponded to siblings’ AGS than to non-relatives’AGS (sign test: C=5, N=22, P<0.030; Fig. 4).Beavers showed no significant discriminationwhen castoreum samples were tested, however (forsniff: T=23, N=12, P>0.100; for physicalresponse: T=27, P>0.100; for total response:T=30.5, P>0.250; Fig. 3; sign test: C=5, N=12,P>0.300 for response completeness; Fig. 4).The mates of dispersers also showed a lowertotal response to the AGS samples from dispersers’siblings than to those from dispersers’ nonrelatives(T=88, N=25, P<0.030). They spentmore time sniffing (T=94.5, P<0.040) and physicallyresponding (T=99, P<0.050) to the AGSfrom dispersers’ non-relatives than to dispersers’siblings (Fig. 5), although the difference inresponse completeness was marginally nonsignificant(sign test: C=9, N=25, P=0.050; Fig.6). Again, when castoreum samples were presented,beavers did not show discrimination fromtheir responses (for sniff: T=21, N=10, P>0.250;for physical response: T=23.5, P>0.250; and fortotal response: T=27, P>0.500, Fig. 5; sign test:C=4.5, N=10, P>0.500 for response completeness,Fig. 6).

DISCUSSIONOur results show that beavers can discriminatebetween AGS samples from unfamiliar relativesand unfamiliar non-relatives. The long dispersaldistance, small home range and territoriality in thebeaver make it unlikely that dispersers and theirsiblings have met since dispersal. We used only thesiblings that were unlikely to have met each otherbefore, based on large distances and land barriersbetween colonies. Consequently, discriminationbetween these unfamiliar siblings must be basedon self-matching (comparing the cue carried by atest subject with that of itself) or matching with athird individual (Holmes & Sherman 1983). Thisresult supports our first prediction that unfamiliarrelatives can be discriminated from unfamiliarnon-relatives. Similar discrimination by dispersers’mates, which were familiar but did not haveany genetic relationship with the dispersers, indicatesthat they can learn cues from beavers theylive with and use the cues to discriminate AGSsamples. This result provides evidence that cuesused for discrimination can be acquired indirectlyvia a third individual as the reference. Therefore,the second prediction from the phenotypematching hypothesis is supported.Phenotype matching has been identified as amechanism of kin recognition in many animalspecies (e.g. Greenberg 1979; Blaustein & O’Hara1981; Buckle & Greenberg 1981; Waldman 1981;Grau 1982; Holmes & Sherman 1982; Getz &Smith 1983; Holmes 1986; Brown et al. 1993).Phenotype matching differs from social learningby a process called cue generalization (Halpin1991). This process allows an individual to learn alimited number of training prototypes (oftenmetaphorically called labels) to form a set ofcriteria (usually called a template) in the sensoryor neural system of the individual. Different individualsare classified into different kin classesaccording to the similarity between the criteriaand the cues these individuals bear (Halpin 1991).Therefore, unfamiliar relatives carrying cuessimilar to those previously encountered can berecognized at the first encounter by this process.Conversely, kin recognition through social learninglacks this cue generalization process (Halpin& Hoffman 1987); hence, a relative carrying anunfamiliar cue will be rejected. Phenotype matchingshould be the predominant mechanism in kinrecognition in situations when related individualsare unfamiliar yet varying degrees of relatednessneed to be discriminated.A test subject may be able to acquire the cueabout kinship used for phenotype matching in twoways: self-learning or learning indirectly from athird individual that is related to the test subject(reviewed in Halpin 1991). Buckle & Greenberg(1981) found that the kinship cue in sweat bees,Lasioglossum zephyrum, can be acquired by selflearningthat cannot be transferred from a thirdindividual. Evidence about whether a cue can betransferred from a third individual is still lacking,however, because it is difficult to separate fromself-learning. Our second test excluded the possibilityof self-learning because the dispersers’ mateswere not related to the AGS donors. Althoughthis test did not examine whether beavers canlearn cues from their relatives, it does provideindirect evidence that beavers have the ability todo so by demonstrating that outsiders can discriminatebetween strangers and individuals froma kin group by learning the cue from one of thekin. Since even an unrelated outsider (i.e. disperser’smate in our study) can learn the cue(s) usedfor kin recognition within a kin group, the mechanismof phenotype matching appears to be usedin a more general context in animal social recognitionthan for kin recognition only.Different scent sources of an individual mayconvey different information (Johnston et al.1993). Our results demonstrate a functional differentiationbetween AGS and castoreum, althoughboth can elicit seemingly similar territorialresponse (Hodgdon 1978; Welsh & Mu¨ ller-Schwarze 1989). No evidence has been shown thatbeavers use castoreum to recognize relativesthrough our study. The castor sacs store castoreumbut lack secretory structures (Svendsen1978). Many castoreum compounds are present inthe food plants of beavers (Mu¨ ller-Schwarze1992), indicating that castoreum compounds arederived from the environment. Although undersome specific conditions, environmentally derivedcues may be used for phenotype matching(Gamboa et al. 1986; Porter et al. 1989), they areconsidered rare (Halpin 1991). In the beaver, dietcomposition changes seasonally and yearly, whichSun & Mu¨ller-Schwarze: Sibling recognition in beaver 499may affect the castoreum constituents. Consequently,castoreum may not be a reliable label forkin recognition by phenotype matching withoutregular contact. In contrast, AGS is the productof a true secretory gland (Svendsen 1978). Onlytwo bacterial species in low density have beenfound in the gland (Svendsen & Jollick 1978), andno evidence has shown that the bacterial contributionto the composition of AGS compounds issignificant. Further study of AGS compositionshows that the variation over time and space issmall (Sun 1996). Therefore, it is suitable foruse in phenotype matching because the label isconsistent.It is not obvious why and how beavers reducetheir responses to the AGS samples from thesiblings of their cohabiting mates. We noticed,however, that yearling beavers (kits) in their natalfamilies normally survived the replacement of oneof the adults (L. Sun, unpublished data). Thisobservation indicates that family reorganizationdid not result in the killing of at least independentyoung beavers (<2 years old) that were still livingin their parental colonies. Young beavers in theirnatal families often help maintain lodges anddams and bring food to infants (Patenaude 1984).The loss of these beavers would mean the loss ofhelpers, which may in turn reduce the reproductivesuccess of new adults. For this reason, it isprobably adaptive to recognize and tolerate theoffspring of new mates. Since recognition byphenotype matching is based on the degree ofmatch between a label and a template, beaversmay not discriminate between the offspringand siblings of their new mates, if the degrees ofmatch are the same. This may be why beaversrespond less to the unfamiliar, unrelated siblingsof their mates, although this issue needs furtherinvestigation.Field studies of kin recognition have a fewdisadvantages. It is often difficult to isolate thevariable(s) of interest from background noise.This usually is not a problem in the laboratory.Another problem in the field is the long timerequired to wait for responses of subjects, makingit difficult to build up a reasonable sample size.Despite these shortcomings, field studies ensurethat artificial effects such as forced choices on testsubjects are minimal, and results may be easier tointerpret in natural settings. Field studies in kinrecognition, although still scarce, have been successfulyattempted in a few species (Waldman &Adler 1979; Beecher et al. 1981; Waldman 1982;O’Hara & Blaustein 1985). Our study using twosamplechoice tests in the beaver has demonstratedthat, with a good understanding of thenatural history of the subjects and a careful experimentaldesign, hypotheses on kin recognition canbe rigorously tested in the field.ACKNOWLEDGMENTSWe thank Diane Chepko-Sade, Axel Engelhart,John Kennedy, Brett Mossier, Mike Rehberg andBoxing Wang for their assistance in our field experiment.Meaghan Boice-Green, Diane Chepko-Sade,Glenn Johnson and Gil Rosenthal helped us withthe manuscript preparation. We are also gratefulto the two anonymous referees for their helpfulcomments and suggestions to our manuscript. Thisresearch was supported by a Sussman Fellowship,an Alexander Wetland Research Award, a DenceAward Fellowship, a Friends of Moon LibraryAward and two grants from the American WildlifeFoundation to L.S. The methods have beenapproved by the Institutional Committee for theCare and Use of Animals.

You know IF id of had to read all of this literature to learn about ANY animal id of probably gone to law school instead of becoming a trapper, lol. The education has been much more enjoyable out in the field vs just reading a bunch of studys.

Paul, like you ive read and heard about that extra toe nail deal on the hind foot however when I was raising that little beaver I noticed he used his front feet more like hands for grooming all the time, so im thinking they use those front feet to apply oil much more than they do that back toe nail!

After each swim he would 'grab' fur with a front foot and squeeze the water out, then lick it off his feet and do the procedure again, was amazing how fast he could get himself dry! This was all done in a very frantic pace as well, lol.

JTrapper,Yes, I would much rather be in the field trapping, or doing ANYTHING other than sit in this office 10-12 hours a day, but, as a grad student, trying to make it in the wildlife profession, I need to be here. I cant wait to get out of school that's for sure.

Yes, I suppose so. I guess it's just kinda cool to me that a beaver can tell from a sniff, if he's related to another beaver he's never seen before, by blood or by marriage. and they are only looking for 2-3 chemical compounds. Humans sure couldnt do that. And maybe dogs can. who knows.

I just thought it was pretty cool, and will certaintly help me shorten the learning curve when I can finally spend some time gettin traps wet. Thought it would help others, too.

Thanks for all your input, Gentlemen. For some reason this post attracted the Trapperman big-wigs! I'm Honored!

WW22, if you want to confirm definitely the sex of a beaver,when you remove the castors and oil sacks theres a little tubethat lies between them (the urethea in the drawing). Feel alongthis tube with your thumb and index finger and if it is a maleyou will feel a small bone inside this tube (the baculum). Onadults it is about 1 1/4 inches long or so and about an 1/8 inchin diameter. On yearlings it is smaller and semi flexible, butstill easily detectable. This bone is non-existent on the females.

Yeah but Jackie....at least he's in the field trapping fur. Others haven't even attempted getting their feet wet nor hands dirty. We need grad students that have field experience...more field experience would be great! Keep at it Wandering...this might need to go to archives.

Buzz, J, Paul and others any of you ever use beaver urine for attractants at sets? I ask because some times when a guy gets ready to skin a beaver ...have you noticed that liquid that leaks out when the beaver is moved? Not sure if thats urine or castoreum?

Jtwappa - "Paul, like you ive read and heard about that extra toe nail deal on the hind foot however when I was raising that little beaver I noticed he used his front feet more like hands for grooming all the time, so im thinking they use those front feet to apply oil much more than they do that back toe nail!"

I have watched them use their front feet for grooming and they do use them a lot. I've seen them use the back feet also. I'm sure they do use their front feet more because of areas that they can't reach with the hind foot.

The few times I've had the opportunity to watch, they seemed to apply spread the oil with their front feet and used their back feet toward the end of the grooming process.

One evening a long time ago I was out hunting moose. Just drifting down a small stream in the boat. I reached a place that looked like a good place to sit and watch so I pulled up and tied off to a live beaver house.

I was amazed at all the vocalizing I could hear in the house. I don't know how many were in there but it was absolutely clear that they were communicating with sounds. It continued for about half an hour or more.

JTrapper....No big bucks being made here! Looking to work for the WIDNR, and I am realy not sure, but, I dont think I will start any higher than 25-30K. If I can even find a job...which isnt likely right now.

Mchewk, Im not sure what the liquid that leaks out is, but I do know that the oil gland comes out all by itself and has a mucular sheath that that squeezes to push some out, while the castor gland has no such sheath. The castoreum is emitted when the beaver urinates on the mound, and comes out by the urine just washing the castor down the tube, so to speak. PLease feel free to correct/modify this statement, all ye sage beaver trappers!

White17, there has been a number of studies on beaver vocalizations, but I havent read any of them. I'f you're really interested, I can scrounge a bunch up and email them to you.